Modification of diet and physical activity behaviors is the cornerstone of treatment for preventing type 2 diabetes in obese adolescents. However, teenagers often are ambivalent about changing behaviors. This ambivalence may underlie poor long-term outcomes with conventional treatment programs. While adolescents want autonomy and may resist advice, they need parental support to achieve success with treatment. Many questions concerning behavioral and metabolic effects of strategies for treating obese adolescents remain unanswered and represent promising areas for future research. From a long-term perspective, Dr. Ebbeling is committed to a career focusing on how motivational and behavioral processes interact with metabolic effects of diet and physical activity to influence maintenance of weight loss and reduced risk for type 2 diabetes. A research career award will provide the opportunity for her to 1) expand her knowledge of type 2 diabetes, behavior change theory, and adolescent health; 2) integrate new knowledge with her expertise in nutrition, physical activity, and obesity in designing innovative motivational interventions; and 3) take a leadership role in conducting a clinical trial. The proposed research project will be a critical vehicle for career development and has important implications for reducing morbidities associated with obesity and type 2 diabetes. The aim of the project is to evaluate a directive, patient-centered counseling style for 1) assisting obese girls (13 to 16 years) in modifying diet and physical activity behaviors and 2) equipping their mothers to provide needed support. Daughter-mother dyads (N=40) will be randomized to Motivational Behavior Change Counseling (MBCC) or Standard of Care Counseling (SCC) for 6 months, with treatments controlled for contact time. According to study hypotheses, changes in primary (diet quality, physical activity) and secondary (body mass index, insulin resistance) outcomes will be more favorable with MBCC compared to SCC. Familial factors that influence behaviors are among several mediating variables that will be explored. In an environment that fosters development of junior faculty, interactions with Drs. Ludwig, Peterson, Sorensen, and Wypij will ensure successful completion of this project and promote Dr. Ebbeling's progress towards independence.